1. Field of the Invention
The field of the invention is a machine control system and in particular a high registration system for generation of photographic masks for photo-chemical processes.
2. Prior Art
It is recognized in the prior art that good registration is required for various photo-chemical processes such as in the manufacture of integrated circuits. The prior art does not distinguish between positional accuracy aand registration, where good registration is achieved indirectly in prior art equipment by providing good positional accuracy. When registration in the magnitude of ten millionths inches is required, systems with positional accuracy in the magnitude of ten millionths inches are provided to achieve this range of registration. These systems are typified by the Photorepeater System, Series 1795, manufactured by the David W. Mann Company; the Automated Microflash Camera, Model 610, manufactured by Opto-Mechanisms Inc.; and the Step and Repeat machine, Model 4M-10AXYL, manufactured by the Jade Corporation. These prior art systems provide ultra-high accuracy positioning with a projection exposure technique. They are very expensive, very complex, and are limited in the registration precision that can be provided.
Prior art machine control systems utilize hardwired logic to process data and to control the machine. The prior art has been discussed in detail in the copending applications that are herein incorporated-by-reference.